Whatever the fortunes of the remaining three concerts from this joint Berlin Philharmonic residency at the Barbican and the Southbank Centre, the bar was set high with its opening chamber concert. Schubert’s 1820 Quartettsatz arguably opens too many quartet concerts – there are not that many overture equivalents – but there was no sense of the routine on this occasion; indeed, from its febrile opening onwards, this C minor single movement emerged far more substantially than is generally the case. Schubert emerged as a more formidable contrapuntist than is often suspected, not least on account of some especially telling viola interventions from Amihai Grosz (the BPO’s first principal viola and also violist in the Jerusalem Quartet). Tempo was flexible, yet never drew attention to itself, following demands or suggestions in the score rather than imposing itself.

For Schoenberg’s Second String Quartet, the players were joined by Anna Prohaska, whose star is unmistakeably in the ascendant. A member of the ensemble at the Staatsoper Unter den Linden, she has recently signed an exclusive contract with Deutsche Grammophon, and will be singing with Claudio Abbado, Maurizio Pollini, and Pierre Boulez later this year. First, of course, the players must fend for themselves – which they did at least as well as they had in the Schubert. A relatively cool opening phrase was answered with music that rightly sounded like Verklärte Nacht turned expressionist, especially when it came to the two inner parts (Grosz and second violinist, Christoph Streuil). ‘Where are we?’ one might well have asked. The score’s dense complexity suggested Brahms, the performance’s dramatic thrust the Schoenberg of Pelleas und Melisande. Despite the audible – even at this stage – pulling away from tonality, the first movement remained definitely anchored in F-sharp minor and sonata form remained capable of operation, albeit in a more compressed fashion than a naïve listener might expect. Yet operate it can, and did: this is 1908, not 1948. The development section brought some wonderfully rich playing from first violin (Guy Braunstein) and viola, the instruments echoing and inciting, whilst the concluding bars ushered in true, pregnant stillness. It is not easy to bring the scherzo off, but these players did so with aplomb, presenting an almost-but-not-quite-fragmentary movement, the ‘not-quite’ bit proved by a properly unifying Schoenbergian Idea. Violence and melodic profusion were shown to be two sides of the same coin, held in dialectical relationship through various forces, not least by a sharp rhythmic profile. The celebrated ‘Ach, du lieber Augustin’ quotation (not ‘Augustine’, as the booklet note had it!) emerged with a cheeky lilt, which lilt and cheek were intensified on subsequent appearances, likewise the fury of the scherzo material. With Schoenberg, as these players readily understood, there is no mere repetition, but developing variation.

It is all too easy to fall into the trap of presenting the soprano as a soloist in the final two movements; she can and must remain part of a ‘string quartet’, albeit a highly unusual quartet-plus-soprano. The players ensured that the mood of a litany (Litanei) was set even before a note had been sung. It was intriguing to note proximity, despite the soprano voice, to the Nietzsche setting of Mahler’s Third Symphony: the Zarathustrian world is deep indeed. Songful, as opposed to aria-like, Prohaska’s delivery imparted a fine sense of line and faultless diction to both of Stefan George’s poems; dramatic flair too, though never straying beyond what was appropriate. Gradually, we seemed to edge towards the world of Pierrot lunaire, and of course, the air of another planet, though Brahms was never entirely banished – nor should he be – from our frame of reference. The final line, ‘gib mir dein glück!’ permitted a step backward, to wonder verbally, and simultaneously forward, to the music that was to come: perfectly judged from all concerned. Entrückung really did seem to bring that long-awaited air: as bracing, rare, and life-affirming as I can recall hearing. Prohaska floated and intoned the line itself: ‘Ich fühle luft von anderem planeten’. How tame so much twentieth-century music seems by comparison! The musicians seemed to place Schoenberg just as he should be placed, yet often is not: his music as erotic as anything in Berg, yet as Alpine as Webern, arguably in this particular case, meta-Alpine. Schoenberg and the quartet showed triumphantly how loss of tonal moorings does not entail loss or even suspension of harmonic direction: there is a whole new world, indeed universe, out there. Again, we seemed but a stone’s throw from Pierrot, and there were a couple of occasions when Ligeti seemed to beckon. For all that, Schoenberg’s music looks back too: I was especially impressed by the chamber-Wagnerian presentation of the line, ‘Ich lose mich in tönen, kreisend, webend’. Chamber Wagner is, of course, precisely what it is: Tristan suggested in words and tones. The vocal climax, when it came, was ecstatic, never forced, after which the strings sounded transfigured, sending shivers down the spine. However, does the consonant ending still work? It could barely have satisfied Schoenberg for long.

Mahler’s early Piano Quartet movement opened the second half. For this, three members of the quartet were joined by the excellent Palestinian pianist, Bishara Harouni. The shading he imparted to Mahler’s opening chords announced a musician of great musical and pianistic gifts. Moreover, blend with the string trio was well-nigh perfect: a far more difficult task than many would assume. The movement’s Brahmsian inheritance proved productive rather than oppressive, its expressive metrical clashes holding no fears for these players. Hushed passages were especially ravishing, Mahler’s prentice work suffering no condescension. I find it difficult to imagine the piece receiving finer advocacy, an impression reinforced by the delicate, heart-rending beauty of the coda in performance.

Sir Simon Rattle and other members of the Berlin Philharmonic ventured onstage for an excellent performance of Schoenberg’s First Chamber Symphony. If the Second String Quartet affirms life more strongly than one might be led to believe, then this sunny masterpiece does so as much as any work by Haydn. I heard Rattle conduct it at the first Prom I ever attended; he has not lost his touch with music of the Second Viennese School. Had I not heard Pierre Boulez lead an expanded Scharoun Ensemble (also drawn from the Berlin Philharmonic) a couple of years ago, I suspect this would rank as the finest performance I have heard. As it was, and belying popular misconceptions of Boulez as a conductor, he managed to elicit just a little more post-Wagnerian warmth from players and score. Nevertheless, Rattle’s remained a fine achievement, flexible without being pulled around, displaying no hint of the mannerisms that have bedevilled some of his more recent music-making. Balance was as faultless as under Boulez: an extraordinary achievement, given Schoenberg’s challenging scoring. The BPO’s woodwind proved as characterful as they had under Karajan (who, I seem to remember, thought the piece well-nigh unperformable), whilst brass sounded both cultivated and vital. Rattle exhibited a sure command of form and character, the foundational status of Schoenberg’s fourth intervals audible for all to hear. The Adagio section sounded both rapt and febrile, not least thanks to some extraordinarily expressive cello playing (Ludwig Quandt). This, then, provided an excellent conclusion to a thoroughly excellent concert.